How to fight potato cancer and is it dangerous for humans?

Potato cancer is a dangerous fungal disease. It was first discovered at the beginning of the twentieth century on the territory of Austria-Hungary, from where it spread throughout Europe.

Thanks to timely preventive measures and the development of varieties resistant to the pathogen, most farmers have never encountered this disease. But forewarned means forearmed.

From our article you will learn how to quickly respond in case of infection and prevent the spread of fungal spores to neighboring areas.

What is potato cancer

Potato cancer is a quarantine disease that appeared at the beginning of the twentieth century. In those areas where infected tubers were found, strict quarantine is introduced to prevent the spread of the pathogen.

The photo shows potatoes infected with cancer.

Features of the pathogen

The causative agent of cancer is a pathogenic intracellular obligate fungus Synchytrium endobioticum (Schilb.) Perc, parasitizing potatoes, physalis, tomatoes, affecting the rhizome.

For reference. The parasite is susceptible to low and high air temperatures. The fungus is most common in countries with temperate climates. In the north, where the ground freezes to -11°C, and in the south, where the soil warms up to +30°C, there is no potato cancer.

The pathogen overwinters in the form of zoosporangia. These are microscopic cysts with a dense shell. In spring, 200-300 zoospores appear from them. Zoosporangia survive in soil for up to 30 years.

The parasite actively develops at soil temperatures of +15...+18°C and humidity of 80%. This environment is ideal for potato development. More than 50% of zoosporangia are formed in June-July, during the period of active tuberization.

Zoospores move through soil capillaries. If within 12 hours they do not have time to penetrate the cellular system of the potato, they die. In a favorable environment, the parasite develops thanks to the toxins it secretes. Neighboring cells enter a phase of intensive division, forming growths. Further, new zoosporangia appear in the center of the growth.

For reference. The life cycle of the pathogen is 12-14 days. Over the entire potato growing season, 15-17 generations appear on the site.

Scientists have proven that if 1 g of soil contains one cyst, the yield loss will be at least 10%. If there are 25 sporangia per 1 g of soil, about 60% of the potato will die.

Varieties of potato cancer

In hot summer conditions, the pathogen takes other forms:

1. Leaf-shaped. The growths on the tubers resemble oyster mushrooms or fleshy foliage.
2. Corrugated. Uneven, lumpy growths appear on the potatoes, and the skin becomes wrinkled.
3. Scabby. A large number of small areas of scab form on the surface of the tubers.
4. Crater-shaped. Convex round new growths with jagged edges, resembling craters, form on potatoes. The diameter of the recesses is 1-1.5 cm.

Sources of infection

Scientists have identified several of the most likely sources of infection:

• farmer's clothing and footwear;
• contaminated working tools;
• excrement of farm animals that were fed infected tubers as food;
• melt water;
• earthworms;
• insects;
• planting infected seed material.

Distribution routes

Potato cancer spreads through infected tubers or potatoes of disease-resistant varieties contaminated with particles of infected soil. Contaminated tools, shoes, animal hooves, and any containers for storing potatoes create a source of disease.

Zoosporangia are transported by meltwater and rain streams from elevated areas.

Having passed through the digestive tract of animals, the spores do not die and, together with feces, return to the ground.

There are known cases of importation of infected seed material from contaminated areas. Negligent attitude to quarantine rules leads to an increase in the area of ​​infection and the loss of a large amount of crop.

Signs of potato damage

It is impossible to recognize the disease during the growing season, since fungal spores do not affect the above-ground part of the plant.

In the fall, after digging, whitish tubercles and dark growths resembling warts are found on the tubers. Their size sometimes exceeds the size of a potato.

The shape of the new growths is similar to cauliflower inflorescences. Smaller bumps form on the stolons.

By the time of harvest, most of the infected tubers completely rot in the ground, the rest - in the first month of storage, infecting healthy potatoes.

Fighting methods

If infected tubers are found on the site, the farmer is obliged to notify the plant protection inspectorate.

Important! Sick potatoes should not be eaten or used as animal feed.

Winter zoosporangium has a durable shell and dies only at a boiling temperature of +100°C. It is better to destroy infected tubers.Scientists have not yet come to a consensus regarding their harmlessness to humans and animals.

Potatoes with cancer are burned along with the tops or thrown into a meter-long hole and sprinkled with bleach, doused with formaldehyde and kerosene.

In the fight against potato cancer, an important role is played by correct agricultural technology, the selection of varieties with immunity to the pathogen and treatment with fungicides. Folk remedies based on herbs and improvised means are powerless against this disease.

Agricultural technology

In spring, only 30% of winter zoosporangia are activated. Agronomic techniques are used to allow the cysts to open, and the zoospores to die without a host plant.

Agricultural methods:

1. Crop rotation. After potatoes, corn, rye, peas, lupines, and beans are planted. The roots of these plants secrete a special substance that promotes the release of zoospores.
2. Application of manure to the soil - 300 kg/100 m². To disinfect the soil in the greenhouse, granular urea is used - 1.5 kg/1 m².
3. Processing seed material before planting.
4. Timely removal of weeds and nightshade tops.
5. Moderate watering. In waterlogged soil, spores spread faster.
6. A ban on the cultivation of perennial grasses in contaminated areas.
7. Selection of potato varieties with cancer resistance. Such crops are sensitive to the influence of zoospores. The affected cell immediately dies, and the cells around it become dense, forming pustules in which the dead parasite is imprisoned. Healthy plant tissue pushes out the pustule, and the wound heals. Agronomists advise planting only such varieties for 5-6 years to completely cleanse the soil of the pathogen. It is advisable to change varieties with cancer immunity every four years to prevent pathogen resistance.

Chemicals

Fungicides are used to disinfect planting material. Tubers are soaked in a 1% Fundazol solution or a 0.5% Benleit solution for 30 minutes. This treatment improves seed germination, increases crop productivity, and strengthens immunity.

To eliminate the source of infection, the soil is treated with pesticides. For 1 m² take 20 liters of a 2% Nitrofen solution. The procedure is carried out only by specialists. Agricultural plants cannot be cultivated on the site for 2-3 years.

Quarantine

List of quarantine measures:

• systematic inspection of potato plantings;
• a ban on transporting potatoes from contaminated areas;
• elimination of foci of infection;
• disinfection of outbreaks in areas with fruit and berry crops.

Danger to humans

Infected tubers do not pose a risk to human health, but It is not recommended to eat disfigured potatoes. The worst thing that can happen when eating diseased tubers is diarrhea.

In any case, this does not make sense, since the product completely loses its taste properties and becomes tasteless.

Potato varieties resistant to cancer

Early ripening potato varieties with immunity to cancer are presented in the table.

Mid-early potato varieties resistant to cancer

Mid-late potato varieties

Disease prevention

To prevent infection of potato plantings:

• observe the principle of crop rotation and plant potatoes in the same place no more than once every four years;
• other nightshade crops are not planted next to potato beds;
• carry out weeding;
• carefully select seed material;
• Varieties with immunity to potato cancer are planted near the quarantine zone.

Conclusion

Potato cancer is often found in areas where the owners do not follow the basic rules of weed removal and crop rotation. The causative agent of the disease is tenacious and remains in the soil for about 30 years.One of the most effective ways to combat the disease is to grow potato varieties with immunity to cancer.

To completely clear the soil of zoospores, it is recommended to plant resistant varieties for 5-6 years, observe crop rotation, disinfect tubers before planting, and carefully select seed material.